For example, Samonella spp and , E.coli are part of the normal flora of the gastrointestinal tract. So how can the identification of these organisms in faecal samples of a dog with diarrhoea be associated with the diarrhoea
This is a much more complicated question than seems at first sight. A related question is why so many animals that eat contaminated or infected food do not all go down with food poisoning.